Electric alarm for locks.



' JA. H. PRESTON. 4 ELECTRIC ALARM FOR LOCKS.

v APPLkIoATIoN' FILED MAB.2,1912. l 1,059,759. Patented A111222, 1913 A A e, i

"ff/77"" W einer erica.

E'Lncfraic enema non. Locks.

. Specification o Letters Patent.

Patented 222, Haiti/..

Application-mcd March 2,' v1912. Serial No. 681,286. I

To aZuZ 'whom t may concern;

Be it known that I, Josiirn HARRIS PRES- 'roN,`of the city of Ottawa, county of'Carleton, inthe Province of Ontario, Dominion of Canada, of the Canadian civilservice, having invented the Electric Alarm 'for Lbcks do hereby ldeclare that the following 1s a specification.

-My invention relates toimproyements in elet'strlc alarms for locks and .tliepbject of the invention is te devise an electric alarm system' in which the circuit will` he closed and a warning given upon the insertionof any instrument or key into the lock', other than the proper key.

A further object is to soY insulate the proper key that it will not close the cir- -cuit when it is inserted into the lock. lattain this 'object lo'y the a plication of electricity to locks and insu ating material to locks and keys illustrated by theaccoln.- panying drawing in which ligure l is a view of a key and a vert-ical section of the walls o a lock. Fig. 2 a vertical section of a portion of the key showfnV Fig. 1. Fig. 3 a vertical section of a partei a key. ig. 4 a view in perspective of the key shown in Fig. 5. Fig. 5 a viewo-.a

' vertical section of part of a key and theiver to the wall d of the lock and is lnsulatedi from wall d by the insulating material f and is connected with one of the -poles m 0f a source of electricity g supplying the annunciator lo.. The other pole n of this source -of electricity is connected to the lo@ at' a point on wall d. l

The metal plate` L is arranged so that a key comes in contact `with it and the Wall c or wall d and thus closes the circuit of the source of electricity g which causes the sounding of the alarmrfrom annunciator lv.

. To the key a in Fig. 1, the insulating material b is fixed as shown also bythe ca b in Fig. 2 and bythe insulating materia on which is the metal cap e as shown in Fig.z

3. The key a does notclose the circuit owing to the insulating material and thus does not cause the soundingl ci t-he alain. from the annuneiator. 1 lo In Fig. 5, the metalplate it h sriveted to it pin i) and is insulated from t e Wall d b 'insulating material f' and is connected wit vone of the poles in, of a source of electricity g supplying annunciator Ic; The other pole n of this source of electricity is connected to `Wall d of the lock.

A key in Fig. 5, comes in contact with wall c or d and'pin p and thus closes the circuit of lthe source .of electricity which causes the soundingofthe alarm .fiom annunciator c.` I

To the liniiigof the key in Fig. 5 is fixed and the key a ing to the contactwith 'pin p ofjthe insulating material on the linin therefore does not causet e sounding'of the alarm. from the annunciator. Iii-Fig.- 6 the wall c is connected with on of the poles m of the sourceo electricit pole n of `this source of Infrlected to wire 7' the end of which is arsupplying the annunciator/c. The .ot er electricity is. con- `insxnliged so that a key comes in contact with it an'fd tl wall c and thus closes the circuit of .thesui'ce of 'electricity g. which causes Vthe sounding of the alarm from annunciator k.

Fig. 7 and the key a does not close the cir cult Iowing to the insulating material 5 andl thus the insertion of key a does not cause the sounding of the alarm from theannunciator In Fig. 9`the wirei is connected one of the poles m of the source of electricity'g of this source of electricity is connected with wire s; the ends of wire r and wirefe; are arranged so that a'key comes in contact with them and thus closes the circuit of the source ofelectricity g which causes the l Out of the s idcof key c in Figsf andI il picese ande. of the. keys are insulated from fthe keyfhy4 the insulating material 5 and `b owing to"th`is' .insulaticn `key a does not close'the cireuitgnor'cause 'the sounding "of the alarmefrom annuncator'J-i.

.What 15de claimas my invention, 'sfirt-se'cure byzLetters Patent, is

electric alarm forllockseox'prising a insulating material b also ,shown in'Fig. 4'

does not close the circuit on'` f of the key @and To the upper edge of key a in Fi 6 is fixed insulating material ,b shown a so in supplylng annunciatcr k. The other pole n sounding oi' the alarm` from annunciator lo.,

and de-4 'zal ice

which insatd frm the main portion of ih@ ,shank and whezeby wheninserted in the lack the circuit-is kept open and Whm'ebyv when anordinary key is insqsrtd in the lock.

plate secured to the back-plaie 05E-fha. lock and insulated therefrom, sa. 'ii'lsula'ed phi@ having :1.11 aperture therein registering with the aperture for ihe pin of ille key in the 5 back plaie of the lmfk, :L source @if electricity The Circuit is closed.

p1a'lc`zu1d the lmuk lock plaie 1'e5pecive1y, ROSE RMSTRONG, 10 A and a key havmg u shank with a pcmlon 0i BLANCH MARY GENIN. 

